Submicron particles suspended in gas can cause serious harm to humans and the environment. One effective method to remove the submicron-sized particles is electrical agglomeration in an alternating current (AC) electric field before the particles are collected in the ESP. In this study, NaCl and Arizona test dust 4 particles laden in an ambient air flow were bipolarly charged in a corona charger, entered a agglomerator, and were collected in a plate-to-plate-type ESP. When an alternating current (AC; 40 kV, 60 Hz) was applied to the agglomerator, the mass concentration of the NaCl particles decreased by 25-27% owing to their attachment to the A4 particles. This decrease was in good agreement with the one theoretically obtained from an agglomeration model considering the wall loss in the agglomerator. When a DC of -4 kV was applied to the ESP, the collection efficiency im proved from 55 to 88% for the NaCl particles. (C) 2020 Elsevier B.V. All rights reserved.